Stored energy refers to the process of storing energy through media or equipment and releasing it when needed. According to the energy storage method, energy storage can be divided into three categories: physical energy storage, chemical energy storage, and electromagnetic energy storage. Physical energy storage mainly includes pumped water energy storage, compressed air energy storage, flywheel energy storage, etc., and chemical energy storage mainly includes lead. Acid batteries, lithium-ion batteries, sodium-sulfur batteries, flow batteries, etc. Electromagnetic energy storage mainly includes supercapacitor energy storage and superconducting energy storage. Today, the editor brings you 11 common energy storage technologies in the power grid:

Energy storage technology exploration

Gravity energy storage

On May 16, 2022, China Tianying and State Grid reached a strategic cooperation on gravity energy storage technology research. The two parties will set up a collaborative team to jointly promote the construction of a 100MWh user-focused energy storage demonstration project in Rudong. Based on the source-grid-load-storage integration technology of "new energy + gravity energy storage", we will continue to innovate gravity energy storage technology, explore the combination model of electricity consumption, power generation, energy storage, and peak and frequency regulation, actively expand the application scenarios of gravity energy storage technology, and promote The diversified application of energy storage technology will accelerate the independence of core energy storage technologies and promote the continued reduction of energy storage costs and large-scale application. State Grid Jiangsu Comprehensive Energy will assist in promoting the project to participate in various power markets such as medium- and long-term transactions, spot, demand response, peak load regulation and frequency modulation auxiliary services. The specific revenue sharing between the two parties will be agreed separately.

Pumped hydro

As of February 2022, the installed capacity of pumped storage power stations in the State Grid Corporation's operating area is 26.3 million kilowatts, and it strives to increase it to 100 million kilowatts by 2030. State Grid's pumped storage capacity in operation and under construction ranks first in the world. The installed capacity in operation accounts for nearly 90% of the company's operating areas, and the installed capacity under construction accounts for more than 80%. On May 9, 2022, the rotor of the fourth unit (No. 4) of the first phase of the Hebei Fengning Pumped Storage Power Station, the world's largest pumped storage power station with the largest installed capacity, was successfully hoisted into place.

All-vanadium flow battery

In response to investor questions, State Grid Yingda stated that State Grid Nari participated in the comprehensive energy project (including vanadium battery energy storage) for the new charging tower on the west side of Hankou Railway Station, and the project has been implemented. State Grid NARI is an institution engaged in battery research of State Grid. State Grid Yingda pointed out in its 2021 annual report that in terms of new energy storage technology, it will accelerate the formation of the commercial operation and implementation capabilities of all-vanadium redox flow battery energy storage systems, based on the safety of use, long life, and full life cycle of all-vanadium redox flow batteries. With the characteristics of low cost, independent output power and energy storage capacity, we will conduct in-depth research and practice on commercial operation models, and actively promote the implementation of all-vanadium liquid flow energy storage demonstration projects.

Lead carbon energy storage power station

On May 28, 2020, the country's first lead-carbon battery grid-side energy storage power station located in Pheasant Town, Changxing, Hubei Province successfully transmitted electricity in reverse. The planned energy storage power of the power station is 12 MW, and the final energy storage power is 24 MWh. It "plugs in" to the power grid for charging when electricity consumption is low, and releases energy to fill the power gap during peak electricity consumption, so as to "shave peaks and filling valleys" to achieve a "balance between power supply and consumption."

Retired lead-acid battery energy storage

The Tongyue Power Supply Station of the Raoyang County Power Supply Company of the State Grid has built and completed the only "source-grid-load-storage coordinated wind, solar, storage and charging direct-use distributed microgrid power supply station demonstration project" in Hebei Province. This project applies decommissioned lead-acid batteries in substations for activation and reuse, completes the energy storage construction of power supply stations, promotes the implementation of a pilot application of activation technology for used batteries returned from substations of provincial companies, and provides first-hand data support for repair and recycling work.

Utilizing battery energy storage step-by-step

State Grid Corporation of China has launched research on large-capacity cascade utilization battery energy storage technology since 2012. In March 2019, the construction of the energy storage power station on the Jiangbei grid side in Nanjing, Jiangsu Province started. This project is the first grid-side energy storage power station with cascade utilization in China. The Jiangbei energy storage power station project utilizes "old batteries" with a total capacity of 75,000 kWh, including 45,000 kWh of lithium iron phosphate batteries and 30,000 kWh of lead-acid batteries.

Compressed air energy storage

China Energy Construction Digital Technology Group Co., Ltd. and Hubei Integrated Energy Services Co., Ltd. jointly invested in the construction of a 300MW compressed air energy storage power station demonstration project in Yingcheng, Hubei Province. A project feasibility study review meeting was organized in Wuhan from December 29 to 30, 2021. . A signing ceremony will be held on February 11, 2022. This project is the largest single-unit compressed air energy storage project in China.

Hydrogen and electricity two-way conversion and energy storage integrated system

On June 24, 2021, at the Binhu Comprehensive Energy Station in Huzhou, Zhejiang, the hydrogen-electricity two-way conversion and energy storage integrated system was successfully put into operation. This is the first application of this system in the field of comprehensive energy supply. State Grid Zhejiang Electric Power has established an industry-university-research-application research team including State Grid Zhejiang Electric Power Research Institute, State Grid Huzhou Power Supply Company, Hangzhou Yineng Electric Power, Zhejiang University of Technology, Hangzhou Pingdan Technology Co., Ltd., Zhejiang Electric Power Design Institute and other units. Successfully developed a hydrogen-electricity two-way conversion and energy storage integrated system, realizing the integration and flexible mutual support of a photo-electricity-hydrogen-pile-storage system. The project applies domestically produced hydrogen production equipment and fuel cells, supporting the localized development of hydrogen energy preparation and application equipment.

Hydrogen energy storage combined heat and power system and lithium battery energy storage system

Jiaxing Power Supply Company has built a multiple energy storage system through a high-efficiency hydrogen energy storage cogeneration system and a lithium battery energy storage system. The multiple energy storage system produces and stores hydrogen during off-peak hours at night, generates electricity heat during peak hours during the day, and provides both energy storage and hot water services to the park.

Solid energy storage heating technology

On July 30, 2021, the solid energy storage heating technology research and development base jointly built by the Hebei Institute of Construction Engineering, State Grid Jibei Electric Power Co., Ltd. Zhangjiakou Power Supply Company, and Hebei Zerui Energy Saving New Energy Co., Ltd. held an unveiling ceremony. It aims to solve key technologies and problems in the fields of energy storage materials and green heating.

Flywheel energy storage

The State Grid Corporation of China is applying flywheel energy storage technology in high-standard emergency power protection. On March 22, 2022, State Grid Jibei Zhangjiakou Wind and Solar Storage and Transmission New Energy Co., Ltd. issued a tender announcement for the joint frequency modulation technology research of flywheel energy storage and thermal power units of North China Electric Power Research Institute Co., Ltd.

Application scenario exploration

Not only in energy storage technology, State Grid also has many explorations in application scenarios.

Mobile energy storage vehicle

In April 2022, Hubei's first 500kW/500kWh multi-functional liquid-cooled mobile energy storage power supply vehicle was officially delivered and accepted. This mobile energy storage vehicle uses third-generation energy storage technology, combining an advanced liquid cooling system with a large-capacity lithium iron phosphate battery, which can quickly connect to backup power in 0.6 seconds and ensure continuous operation for at least 18 hours.

Mobile energy storage system

On May 28, 2020, the mobile energy storage system developed by State Grid Xiongan New Area Power Supply Company and Pinggao Group was officially connected to the grid and put into operation. This mobile energy storage system uses a dual-mode energy storage converter as the grid-connected interface. It uses an intelligent software platform and monitoring hardware to detect power outages and power restoration conditions during construction and serves as a backup power supply to realize automatic and off-grid connections. Seamless switching can effectively improve the reliability of construction power supply.

Grid-side energy storage frequency modulation

In February 2021, the substation supercapacitor microenergy storage device independently developed by State Grid Jiangsu Electric Power Co., Ltd. was put into operation. It can respond quickly to power, actively suppress grid harmonics, flexibly adjust reactive power, improve power supply reliability, and help the grid operate more efficiently. Safe and reliable. On November 16, 2021, the State Grid Tianjin Electric Power Research Institute completed the research on the primary frequency modulation performance test plan of the Binhai Xudao Energy Storage Power Station.

Thermal power-energy storage joint frequency modulation

In October 2021, technical personnel from the State Grid Shandong Electric Power Research Institute completed the independent research and development of the thermal power-energy storage joint frequency modulation function of the network source platform, realizing functions such as energy storage capacity configuration optimization and control strategy optimization. Thermoelectric energy storage In April 2022, the State Grid Times Huadian Datong thermoelectric energy storage project started. The project adopts the latest generation of all-outdoor prefabricated cabin design. The energy storage system uses lithium iron phosphate batteries with a scale of 150MW/300MWh. After being put into operation, the energy storage power station will actively accept grid dispatching and participate in auxiliary services such as grid peak shaving and frequency modulation.

New energy side peak regulation and frequency modulation

On June 12, 2020, a negotiation meeting on investment cooperation projects between Yumen City, Gansu Province, State Grid Integrated Energy Services Group, and Shanghai Electric Energy Storage Power Station was held. The strategic cooperation between State Grid Comprehensive Energy and Shanghai Electric is investing in energy storage power stations in China. It plans to invest in the construction of a 100MW/200MWh scale energy storage power station in Yumen, Gansu Province to assist the power grid in peak and frequency regulation and promote the consumption of new energy.